Source : Webster's Revised Unabridged Dictionary (1913)

Thrush \Thrush\, n. [OE. [thorn]rusche, AS. [thorn]rysce; akin
   to OHG. drosca, droscea, droscela, and E. throstle. Cf.
   {Throstle}.]
   1. (Zo["o]l.) Any one of numerous species of singing birds
      belonging to {Turdus} and allied genera. They are noted
      for the sweetness of their songs.

   Note: Among the best-known European species are the song
         thrush or throstle ({Turdus musicus}), the missel
         thrush (see under {Missel}), the European redwing, and
         the blackbird. The most important American species are
         the wood thrush ({Turdus mustelinus}), Wilson's thrush
         ({T. fuscescens}), the hermit thrush (see under
         {Hermit}), Swainson's thrush ({T. Alici[ae]}), and the
         migratory thrush, or American robin (see {Robin}).

   2. (Zo["o]l.) Any one of numerous species of singing birds
      more or less resembling the true thrushes in appearance or
      habits; as the thunderbird and the American brown thrush
      (or thrasher). See {Brown thrush}.

   {Ant thrush}. See {Ant thrush}, {Breve}, and {Pitta}.

   {Babbling thrush}, any one of numerous species of Asiatic
      timaline birds; -- called also {babbler}.

   {Fruit thrush}, any species of bulbul.

   {Shrike thrush}. See under {Shrike}.

   {Stone thrush}, the missel thrush; -- said to be so called
      from its marbled breast.

   {Thrush nightingale}. See {Nightingale}, 2.

   {Thrush tit}, any one of several species of Asiatic singing
      birds of the genus {Cochoa}. They are beautifully colored
      birds allied to the tits, but resembling thrushes in size
      and habits.

   {Water thrush}.
      (a) The European dipper.
      (b) An American warbler ({Seiurus Noveboracensis}).

Thrush \Thrush\, n. [Akin to Dan. tr["o]ske, Sw. trosk; cf. Dan.
   t["o]r dry, Sw. torr, Icel. [thorn]urr, AS. [thorn]yrr, OE.
   thrust thrist, E. thrist.]
   1. (Med.) An affection of the mouth, fauces, etc., common in
      newly born children, characterized by minute ulcers called
      aphth[ae]. See {Aphth[ae]}.

   2. (Far.) An inflammatory and suppurative affection of the
      feet in certain animals. In the horse it is in the frog.

Source : WordNet®

thrush
     n 1: candidiasis of the oral cavity; seen mostly in infants or
          debilitated adults
     2: a woman who sings popular songs
     3: songbirds characteristically having brownish upper plumage
        with a spotted breast